The present invention relates to systems for testing a manufacturing of an article, or the like, such as a memory device. In particular, the present invention relates to a system for evaluating and comparing data from two manufacturing tests performed during the manufacture of memory devices and then providing a consumable output to identify the relation between the data from the manufacturing tests.
Exercising a semiconductor-type memory device during manufacturing for testing purposes is known. Such exercising can include running all ones or zeros through the device and then recording the output, or running checkerboard patterns, digit stripes, double digit stripes, or other pattern mechanisms or ways of writing to a device, and comparing the actual output to an expected output for a given set of conditions such as supply and substrate voltage, or conditions with regard to timing, etc.
The results of such exercises are evaluated to provide information on the device and the testing process. Outputs of such tests are collected and a determination made as to whether the device had passed or failed. Data accumulated from the tests is logged, but each engineer or tester who wants to look at the data in order to make comparisons must go through the data by hand. If a change is to be made to the testing process, testers run a second sequence of tests on the device previously tested. Such test sequences could be used for, for example, to catch a new error mechanism or to eliminate a redundant test. To date, this evaluation has been done by hand.
Calculating repair solutions as a function of the testing process is also known. In the case of repair solutions, performed on a per die basis, this system was only feasible as long as the number of dice remained relatively small. As die sizes decreased, and as wafer sizes increased, thus increasing the number of dice, the number of repair solutions, increased geometrically. Consequently, the manual evaluation of data became overly burdensome. Even when the evaluation of test results became automated, the sheer amount of data that a test could provide prevented a thorough evaluation of all of the test results. For example, some manufacturers opted to analyze the data only after the tests were performed, and then only consider summaries of test data.
What is needed is a mechanism to evaluate all relevant data across independent test procedures and to provide a consumable output to give the tester an accurate account of the test results. In addition, what is needed is a way of present repair solutions which allow a facile comparison of different approach to generating the solutions.